Elevator control system



Aug. 4, 1931. w EAMES 1,817,509

' ELEVA TOR CONTROL SYSTEI 7 Original F iled Jan. 25, 1928 Fig.1.

INVENTOR William F. Eame's A'TTORNEY Patented 4, i931 UNITED STATES PATENT OFFICE 1, 1mm or mxmwoon, PENNSYLVANIA, assrouoa T0 wrisrmonousn 5: ammo & mac'mnmo courmnmn coaroasrrou orrrnnnmvam nuvaron conrnor. sYsTEJu 7 Application fl a January a, 1928, Serial 110,249,274; aene ea memb r 17', 1s s' o.-

The invention relates generally to control systems and more. particularly to systems for controlling the operation of electric elevators, hoists and other similar machinery.

In operating elevators ofthe variablevoltage type in places where the ;constant service not required except at intervals throughout the day or the operation is very intermittent in character, such, for example,

' w as in apartment houses, it has been found very uneconomical to keep the motive means in continuous operation under its own power.

' nce the driving motor for the generator in variablevoltage and similar control systems must necessarily be of suificient capacity for the ordinary operating load, its continuous operation, when the elevator is idle for long periods of time, results in low- 7 go ering the power factory of the supply circuit, which, for well-known reasons, is very undesirable. Furthermore, the no-load losses of a, large motor,,extending over a considerable length of time, become'quite 26 appreciable when compared with the useful power consumed. c. v V The f object 01 the invention, generally st'atefd,,is, to provide a control system for electric elevators which shall permit ecoso nomical 0 .erati'on under intermittent operating coniti'ons.

A m re pecific Object. of the invention is I to provide, in a variable-voltage elevator control system, an auxiliary motor for driving the motor-generator set, at a speed fcor- I responding to its normal operating speed, to permit the main motor to be disconnected from the supply line. during such time as the elevator is idle.

A further object: of the invention is to provide for reducing the no-load power 1 of an intermittently operated electrio-elevator system. I

Another object of the invention is toprovide for increasing the average power factor of an intermittently operated electric-elewater system.

other Obje t f th n ention will b 00 come evident from the following descriptherein shown is suitable for operating "a source of excitation for the, field windi'ngs tion, taken in conjunction with the 'accom-' panying drawings, inwhich 7 Figure 1 is a diagrammatic view of a; variable-voltage elevator=control systemlem bodying my invention, andl I F ig. 2 is a diagrammaticview of an electrical machine which ma be utilized to pro vide a modification of the syste'rn shown in fieferring to Fig. l,'the'control system' single elevator. As shown, the elevators stem' comprises an elevator car C, suspen ed in a hatchway by means of a hoisting cable Ca which passes over a hoisting drum D to a suitable counterweight CW, in the usual manner. p p The hoisting drum D maybe driven in any suitable manner and, as illustrated, is" directly coupled to an elevator motor EM having an armaature EM and separately excited shunt field winding EMF. v As shown, the control for the elevator motor EM is of the variable-voltage or Ward- 7 Leonard type, wherein a motor-generator set, comprising a direct-current generatorG and main driving motor M, is provided. The generator G is of the variable-voltage compound-wound type having an armature winding VGF and a demagnetizing field duction motor M, having a stator I MSand a squirrel cage rotor M, is provide As shown, the rotor M is directly connected to the armature Gc i 1,

In order to "provide a. direct-current,

c c. of the generatorfG and elevator motor EMF and to operate the various control switches,

a direct-current eXciter 'E, having a field winding EF and armature E i sj uti lized.

' G, a seriesfield winding GSF Shunt e ;:.t-.

The elevator motor EM is controlled, in the usual manner, through the agency of a car switch CS on the car C, the usual up and down direction switches, designated as 1 and 2, respectively, a motor-circuit control switch 3 and a speed switch 4.

In the operation of an elevator-control system of this type, it is the usual practice to continuously operate the motor-generator set, which supplies power to the elevator motor, from the power derived from the main motor M. However, in this particular embodiment of the invention, an auxiliary motor AM is provided to cooperate with the main driving motor M in a manner which will be described in detail hereinafter.

In order that a more comprehensive understanding of the invention may be obtained, a description of the operation of the system, when operating in accordance with the present invention, will now be given.

In order to provide power for operating the elevator, the motor-generator set, comprising the motor M and gene 'ator G, must first be set in operation. The motor-generator set may be started in operation by actuating a switch 5 to the closed position, which establishes an operating circuit for the auxiliary motor-line switch 6 extending from the conductor L1 of the multi-phase power supply comprising the conductors L1, L2, L3, through conductor 7 operating coil of the line switch 6, conductor 8 and switch 5, to line conductor L2.

Upon closure of the auxiliary motor-control switch 6, a multiphase energizing circuit is established for the auxiliary motor AM, one phase of which may be traced from the line conductor L1, through conductors 7 and 9, contact members a of the switch 6, conductor 11, resistor 12 and conductor 13 to one phase of the stator winding AMS: a second phase extends from the line conductor L2, through switch 5, conductors 8 and 14, contact member Z) of the switch 6, conductor 15, resistor 16 and conductor 17 to a second phase winding of the stator AMS, and a third phase extending from the line conductor L3, through conductor 18, contart member 0, of the switch 6, conductor 19, resistor 21 and conductor 22 to the third phase winding of the stator AMS. The resistors 12, 16 and 21 are included in the auxiliary motor circuit, as described, to permit the auxiliary motor AM to accelerate to full speed without drawing excessive current from the line. As will be observed, a shortcircuiting switch 23 is provided for shortcircuiting the resistors 12, 16 and 21 from the auxiliary motor circuit after a certain predetermined time. The particular switch, as illustrated, is provided with an actuating coil 24 and a dash-pot 25 and operates in a. well-known manner, in which the actuating coil 24 becomes energized as soon as the motor circuit is completed, but the closure of the contact members is retarded by the action of the dash pot 25.

Assuming the elevator he at the first floor, the attendant on the car may start the car upwardly by 1(iLU g the handle 26 of the car switch C5 to t 'iirst point in the left position, as viewed in the drawing, thereby bridging the contact fingers 2S and 29 and compl an operating circuit for the up dire 1 switch 1 extendin from line conductor 4, through conduc'or 27, contact memhe 2S and 29 bridged by the movable segmti-it 31, conductor 32, operating coil of the switch 1, normally closed contact memb rs a of the d direction switch 2, conductors and 3-4, operating coil of the swito and conductors 35 and 36 to the line conductor L5. 7

The up direction switch 1 closes its contact ineinbe as Z) and 0, thereby supplying the generator shunt field winding G1 with exciting current in one direction through a circuit which extends from line conductor L4, through conductor 37, contact members 0 01" the up direction switch 1, conductor 38, field resistor 39, field winding GF, contact members b of the up direction switch 1, and conductors 41 and 36 to the line conductor L5.

Simuitaneously with the closure of the up direction switch 1, the contact members a of the elevator motor switch 3 closed to connect the arinat r of the generator G in loop circuit with the elevator motor arn'iature EM, as shown. However, sin e motive power other than from the auxiliary motor AM is now required for operat ng the generator, the switch 3 is prowith contact members 6 which are videt also simultaneously actuated to the closed position to establish an operating circuit for the main line switch 43 ot the main motor M. As shown, the switch operating circuit extends from the energized conductor 8 through the operating coil of the switch 43, conductor 44, contact members b of the switch and conductor T to the line conductor Ll. Upon the closure of the line switch 43, the stator winding MS of the motor M is connected to the multi-phase power supply from the energized conductors 9, 14 and 18, through the contact members a, Z) and c of the switch conductors 45, 46 and 47, as shown.

In order to accelerate the elevator to full speed, the car switch CS is actuated to the second position, where the movable contact member 31 engages the contact finger 48, thereby completing an operating circuit for the speed switch 4, ich, as shown, is disposed to short circuit the resistor 39 in series with the gen rater shunt field GS. The operating circui u for the speed switch 4 may be traced from the iine conductor L4,

through'conductor 27, contact members '28 and i8 brid dby the movable segment 81, conductor. 4 operating coil of thespeed switch 4 and conductors 50, 41 and'36 to line conductors L5.

- It will be readily understood that, upon The operation of the elevator full speed in the up direction may be continued until the operatinghandle 26 of-the car switch CS is notched back to the first posi tion, whereupon, the operating circuit for the speed switch 4 is interrupted, which inserts the resistor 39 in the generator-field circuit, thereby automatically decelerating the elevator motor EM. Upon further movement of the car switch to its initial or oil position, the up direction switch 1 and switch 3 are deenergized and, there fore, open to deenergize the generator shunt field circuit and disconnect the motor M from the power supply.

Since it is desirable order to brin the elevator motor'. to. rest quickly and e ciently, the generator-demagnetizing winding GAF'is disposed to become energized upon the opening of the up direction switch 1. In" thisevent, a circuit is established from one terminal of the armature G through the field winding GSF, demagnetizing winding GAF,'condnctor 52,

contact members d of the down direction switch 2, contact membersd'of the up direction switch 1, conductors 53and 54to the opposite terminalof the generatorarmature G. The efi'ect of this winding to quickly reduce the magnetism in the gen of a strong field under the influence of residual magnetismin the 'field, 'aided the strong series field winding GSF, and thus prevent creeping of the motor through the brake (not shown) after exciting current is no longer supplied to the separatelyexcited field winding GF. i i

It will be observed that the operation of V th ux'l' r ot AM is c letl c e a 1 m y m or omp e y on embodiment of the invention may be readily trolled by the switch 5 and, therefore, the

. operation. of the main control apparatus does not affect the operation of the auxiliary motor AM which continues to drive the motor-generator set'and the excite'r E at a speed corresponding to its normal operating sp y ,I Itwill be readily understood thatthe operation of the system. is such that the driv ,ing motor M of the motor-generator may be successively energized and deenergiied in" accordance w th the operation "of the elevator, since the rotating parts are. constantly to demagnetize the generator field as quickly; as-possible, in

- vator'is commutator-and-brush assembly 56 and, at-

theother end, with a plurality of slip rings 57, in .a manner which is ordinarily used in the construction of rotary converters. A shunt field winding 58 is wound upon the usual type of field poles and a squirrel-cage winding 59 iswound in the pole faces as shown.

It'will be readilyunderstood that, in utilizing a combination-:exciter and auxiliary motor of this type, the machine, upon becoming energizedeon the three-phase side, through'theslip rings 57 starts as a squirre1-- cage induction motor. As the speed of the armature 55 increases, a direct-current voltage is developed whichautomatically energizcsfthe shunt field winding 58, the machine 0 crates as a synchronous motor from the aternating-current side. I v

Since the full-load speed of the drivin motor M of the motor-generator set woul in'this case, be less than the synchronous speed of the combination motor and exciter, provision musttbemade to disconnect the latter from the supply source whenever the motor M is energized. In this particular embodiment of the invention, the motor switch'43 is provided with additional con tact members D, E and F, which are nor-r mally closed and, therefore, interrupt the power circuit to the combination motor and excit'er' whenever the switch 43 is operated I erator field, thus preventing the building up its s P it to connect the mail! motor M tolthe supply source. v

It has not been deemed necessary to describe the operation of the system when the elevator'is travelling in the down direction, it beingobvious that the operation is the same, with the exception that the down direction switch 2 is energized instead of 118 the up direction switch 1.-

It will be readily understood that either ap lied to any elevator-control system of this type whereina motor-generator set is 126 utilized 'for supplying power to the elevator motor, and it is particularly advantageous where only-intermittent operation of the eleesired andwhere heavy penalties are imposed upon the power" user for permitting his system to operate at a low or undesirable power factor. I The described embodiments ofmy invention being merely illnstrative,I do not de- -si e 'tobe limited to the exact details of to the ele the apparatus disclosed, except as they are defined in the appended claims.

I claim as my invention:

1. In an elevator control system, in combination, an elevator, a motor for operat ng the elevator, controlling means for starting and stopping said elevator motor, a generator for supplying power to said elevator motor, a motor for driving the generator when the elevator is in operation, a power supply for said motor, means operably' responsive to actuation of the control means to start said motor for connecting said dr1ving motor to the power source and means operable to maintain the driving motor and generator in operation when said motor has been disconnected from the power supply.

2. In an elevator control system, in combination, an elevator, a motor for operating the elevator, control means for starting and stopping said elevator motor, a generator for supplying power to said elevator motor, a main drive of sutlicient power to operate said genera-tor when the elevator motor is fully loaded, an auxiliary drive of less power for operating the enerator when said elevator motor is idle, and means operably responsive to actuation of said control means to start said elevator motor for starting said main drive.

In an elevator control system, in combination, an elevator, a motor for operating the elevator, a motor-generator set for supplying power to said elevator motor, an auxiliary motor for starting the motor-generator set, a power supply, a switch for connecting the auxiliary motor to the power supply, an elevator control switch, electromagnetic means responsive to said control switch for connectin the enerator to the elevator motor, and electromagnetic means controlled by the elevator control switch for connecting the driving motor of the motor- .generator set to the power supply.

at. In an elevator control system, in combination, an elevator, a motor provided with a field winding for operating the elevator, a motor-generator set for supplying power vator motor, said set comprising a direct-ciu'rent generator provided with a field winding and an alternating-current in duction motor disposed to drive the genera tors, a power source for the motor-generator set, means for controlling the opera tion of the elevator motor, said means being disposed to alternately connect and disconnect the alternating-current motor and the source of supply when the elevator is operated, and means for exciting the field windings of the elevator motor and generator, said means being operable to drive the motor-generator set when the main motor is disconnected from the power supply.

5. In an elevator control system, in combination, an elevator, a motor provided with a field winding for operating the elevator, a motor-generator set for supplying power to the elevator motor, said set comprising a direct-current generator provided with a field winding and an alternating-current induction motor disposed to drive the generator, a power source for the motor-generator set, means for controlling the operation of the elevator motor, said means being disposed to alternately connect and disconnect the alternating-current motor and the source of supply when the elevator is operated, and a combination motor and exciter, said motor and exciter comprising a generator element for exciting the field windings of the motor and generator and a motor element disposed to drive the motor-generator set when the alternating-current driving motor is disconnected from the power source.

6. In a control system for an elevator car, a source of power for said system, a work motor for operating said elevator, a generator for supplying power to said work motor, a motor for driving said generator, a second motor for driving said generator, switching mechanism for connecting one of said motors to said source, control mechanism operable to cause said work motor to start said elevator, and means adapted after operation of said control mechanism to connect the other of said motors to said source.

7. In a control system for an elevator. a source of power for said system; motive means for said elevator comprising a work motor for operating said elevator, a generator for supplying power to said work motor, a main motor for driving said generator, and an auxiliary motor for driving said generator; and a controller for said motive means including switching mechanism operable to cause connection of said auxiliary motor to said source of power, control mechanism operable to cause said work motor to start said elevator, and means responsive to operation of said control mechanism to connect said main motor to said source of power.

8. In a control system for an elevator car, a source of power for said system, work motor for operating said elevator, a generator for supplying power to said workmotor, a main motor for driving said generator, an auxiliary motor for driving said generator, switching mechanism for connecting said auxiliary motor to said source, control mechanism operable to cause said work motor to start said elevator, and means responsive to operation of said control mechanism for connecting said main motor to said source, said last named means being effective regardless of the load supplied said work motor by said generator.

9. In a control system for an elevator, at power supply for said system, a work motor for operating said elevator, a generator for I supplying power to said work motor, a main mechanism rendered efiective' upon movement of said switchto said second position to cause said work motor'to start said elevator, and means also rendered effective upon movement of said switch to said second position for connecting said main motor to said source and for disconnecting said auxiliary motor from said source.

10. In a control system for an elevator, a work motor for operating said elevator, a generator for supplying power to said work motor, a main motor for driving said generator, control circuits and mechanism for controlling said circuits including a switch movable from an initial to a starting position to cause said work motor to start said elevator, and an auxiliary dynamo electric machine adapted while said switch is in said initial position to operate as a motor and drive said generator, and adapted while said elevator is in operation to operate as a generator and supply power for said control mechanism. i

11. In a control system for an elevator, a main source of powerfor said system, a direct current work motor vfor operating said elevator, a direct current generator for supplying power to said work motor, said generator havinga shaft, a main motor for driving said generator, control circuits and mechanism for controlling said circuits 1n-' eluding a switch h'avingan initial and a car starting position, and means for maintaining said generator .in rotation while said switch is in said initial position and for supplying direct current for said control mechanism comprising a translating device, connections between said main power supply and said translating device and between said control circuits and said translating device, and means for mechanically connecting said translating device to said generator shaft. I

12. In a control system for an elevator, asource of laternating current for said system, a direct current workmotor for operating said elevator, a direct current generator for supplying power to said work motor, said generator having a shaft, a controller for said system including control apparatus and circuits associated therewith, and means for driving said generator and for supplying direct current for said control apparatus, said means comprising a translating device, connections between said translating device and said alteranting current source and between said translating device and said control circuits, and means for mechanically conling said circuits including a switch having an initial and a car starting position, and means for maintaining said generator, in rotation while said switch is in said initial position and for supplying direct current forsaid control mechanism comprising a translating device, connections between said alternating current source and said translating device and between said control circuits and said translating device, andmeans for mechanically connecting said translating device to said generator shaft.

14. In a control system for an elevator, asource of alternating current supply, a direct current workmotor for operating said elevator, a direct current generator for supplying power to said work motor, said generator having a shaft, a main alternating current motor for driving said generator, control circuits-and mechanism forcontrolling said cireuitsincluding a switch having an initial and a car starting position, means for maintaining said generatorin rotation while said switch is in said initial position and for supplying direct current for said control mechanism comprising a translating deviee, connections between said alternating current source and said translating device and between said control circuits and said translating device, means for mechanically connecting said translating device to said generator shaft, and means responsive to movement of said switch to said car starting position for connecting said main driving motor to said alternating current source and for interrupting the connections between said translating device and said alternating current source.

In testimony whereof, I have hereunto subscribed my name this'23rd day of J an.- uary, 1928. V

. 1 WILLIAM F. EAMES. 

